Electric bus rapidly recharges using wireless charge plates at stops

An electric bus has been developed that can recharge wirelessley
as it makes each stop, regardless of weather conditions and even if
the bus isn't lined up perfectly with the charge plate.

It's the practical culmination of earlier research at Utah State University into wireless recharging -- in July 2011,
the Wireless Power Unit (WPT) at the university had demonstrated a
way to transfer five kilowatts of energy across a 25cm gap with 90
percent efficiency using the principle of electric induction. That
technology is now mounted on the underside of a bus as a large
plate, with another plate mounted in the road next to the bus's
stops. At each stop, the bus takes on charge, meaning electrically
powered large vehicles could potentially end up as viable as ones
powered by combustion engines.

A problem with making vehicles that drive all day (like buses)
electric is that they eventually have to recharge, and that means
either accepting gaps in service while that recharging takes place
or investing in several vehicles to cover a route which previously
only needed one. The charge plates developed by the WPT team can
handle a peak transfer of 25 kilowatts, and usefully it can handle
a misalingment of up to 15.24cm. That means the bus driver doesn't
have to stop at a precise point to charge, which would negate the
usefulness of a system which otherwise doesn't require fiddly
cables or other equipment.

The 12-metre-long bus is expected to go into operation on Utah
State University's campus, with the charge capacity increased to 50
kilowatts. The project to develop the charging mechanism was
funding by a £1.6 million grant from the US Federal Transport
Authority, so presumably this technology is planned for greater
things than just a university hopper bus. Wesley Smith, the CEO of
Wave (a company affiliated
with Utah State University which was involved in the WPT's
development), was quoted as saying that he expects that "on certain routes" the
bus will be "cheaper than gasoline" -- potentially as much as a
fifth cheaper.

The possibility of charging electric vehicles as they drive is
exciting, because it solves both the problems of "range anxiety"
(the battery never gets a chance to run down) and battery size
(frequent chances to recharge mean batteries can be smaller, and
thus vehicles can be lighter).

Wired.co.uk reported earlier this year on a Japanese team that developed a
way to transfer electrical energy through concrete, which could
also lead to a future where cars draw their energy directly from
roads -- but the technology will have to be developed further, as
currently it only manages an output great enough to power a dim
lightbulb. A system of plates in the ground at designated stopping
points like traffic lights or stop signs could be more
practical.